The Naval technologyresearch tree unlocks new ships and technologies related to naval invasions. It can be found between the land doctrine and naval doctrine tabs in the research interface. There are a total 31 different technologies within the naval tree: 28 ship classes organized into seven types and three naval transport technologies. Note that the first naval transport technology, Transport Ship, is required to execute naval invasions. Also note that a blue diamond on a ship's portrait indicates that it is a capital ship; capital ships are designed to sink enemy ships in surface battles and are capable of providing shore bombardment except for aircraft carriers which provide bombardment via their close air support (CAS) planes.

The lightest screening vessel. Screens are very important because they defend the larger ships from enemy small ships that can carry torpedoes (torpedoes have a lower hit chance but when they hit they do a ton of damage on large ships). Destroyers are cheap screens that can evade large caliber fire, add anti-air capabilities, and let you detect and neutralize submarines.

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Technology

Year

Basecost

Prerequisites

Description

Effects

Destroyer I

1922

127.5

To ensure the safety of convoys, the destroyers of the Great War must be repurposed and developed. Arming vessels with more torpedoes will allow more opportunities to engage.

Light Cruiser - A light screening vessel. Cruisers are good at taking out other screens. Its primary duty is to shield capital ships from enemy light ships that carry torpedoes, but it can also unleash powerful torpedoes that are capable of hurting bigger ships if they get close enough.

Heavy Cruiser - A large armored cruiser that is pretty flexible. A good choice for nations who can't afford to build larger capital ships. Heavy cruisers can take a lot of hits and carry a lot of firepower.

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Technology

Year

Basecost

Prerequisites

Description

Effects

Light Cruiser I

1922

127.5

Maneuverable light cruisers that can maintain a high speed will continue to be useful for scouting missions.

As restrictions are increasingly ignored worldwide, more balanced heavy cruiser designs with more priority on armor can be built. Better anti-air guns allow these ships to cooperate in naval air warfare.

The largest capital ship with the biggest guns and strongest armor that money can buy. Such an expensive investment deserves proper support of smaller screening ships. Battleships can take a lot of hits and carry a lot of firepower.

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Technology

Year

Basecost

Prerequisites

Description

Effects

Battleship I

1922

127.5

Considered by some to be a relic of a bygone era of naval warfare, by others as the most impressive ships ever built, no one can deny that these remnants of the battleship arms race constitute some of the most heavily armed and armored vessels ever built.

Thicker armor, stronger engines, a battery of high-caliber guns and improved anti-air capabilities can allow battleships to remain relevant, if correctly employed, in a world where naval warfare is increasingly dominated by aerial support.

The current state of the world no longer has any room for abiding by naval treaties. Without these limitations, we can focus entirely on creating the heaviest, most well-armed battleships of all time, able to engage multiple lesser vessels.

The role of the submarine is to hunt down enemy shipping and not have to challenge a superior enemy fleet directly to hurt them. Submarines employ stealth and powerful torpedoes to destroy enemy convoys. Submarines can also fill a role in regular fleet combat should the enemy be low on submarine detection. A submarine starts out hidden and is either spotted if it gets too close to a destroyer or after firing a torpedo after which it will try to escape. It won't be an effective weapon against an enemy with a proper fleet, but unescorted capital ships won't have much defense.

The goal of the submarine is primarily to attack your enemy's economy by preying on convoy routes. For example:

Attacking convoys along an enemy trade route will deny them foreign resources.

A nation split across the globe like Britain must convoy home resources to their capital area from many places in its empire to use them, making them vulnerable to submarine raiding.

When receiving lend lease, convoys carrying equipment can be sunk and will be lost forever.

When deploying troops on foreign theaters of war a nation must ferry supply and reinforcement equipment to them. By taking out these convoys their troops will be weaker and easier to defeat.

Troops being transported or during a planned invasion may be attacked leading to them being wiped out or severely weakened. You always want to be very careful and guard your transport routes before sending troops somewhere in war time.

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Technology

Year

Basecost

Prerequisites

Description

Effects

Submarine I

1922

127.5

Submarines are stealthy vessels designed to take out undefended convoys. The early models from the Great War pave the way for new methods of naval warfare.